1. Field of the Invention
This invention relates to orthopedic prostheses used to align, to draw together and to generally set long bones of the body which have been fractured, and more particularly, to a device used to assure that screws can be extended through fractured long bones of the body at a location such that the axes of the screws and the holes in the bone through which they are inserted line up precisely with the axes of screw-receiving holes formed through the distal end of an orthopedic fastening nail employed in an intramedullary position within the fractured bone of the patient.
2. Brief Description of the Prior Art
In orthopedic surgery, a technique utilized in the setting of fractured long bones of the body has entailed placing in the medulla of the fractured bone, an elongated hollow stainless steel shaft, often termed a "nail", which extends coaxially within the bone, and provides rigidity and alignment to the fractured bone. The nail is characteristically provided with transverse apertures at its opposite ends through which fastening devices, such as screws, may be passed and extended into the bone on opposite sides of the nail. The nail is thus anchored against shifting or movement relative to the bone. Since the nail is, at the time of screw implacement, located within the medulla of the bone, and the bone within the flesh of the limb that is involved, it is not possible to visually discern the location of the screw holes through the nail. It is therefore very difficult to achieve the required precision of alignment to be assured that the screws will enter the screw holes in the nail, and pass clearly therethrough on the first attempt at alignment.
For various reasons, it is much easier to successfully achieve the extension of the screw through the hole provided in the proximal end of the nail, than it is to properly align and successfully extend the screws through the pair of spaced screw holes formed transversely through the distal end of the nail. For the purpose of achieving such placement of the distal screws, various instruments have been devised and various procedures proposed. The more recent of these have involved, in general, the use of some type of drill jig which is employed in conjunction with an x-ray device to permit x-ray aligned or located drill hole paths to be accurately formed so that the screw holes provided through the bone on opposite sides of the nail are hopefully precisely aligned with the screw holes through the nail, and the screws may then be properly emplaced quickly and with no difficulty.
A recent device and technique utilized for installing an implanted orthopedic prosthesis in the form of an elongated nail or rod placed in the medulla of a fractured bone is disclosed in Taylor et al U.S. Pat. No. 4,667,664. The function of the device disclosed in this patent is to locate the blind screw holes formed in the distal end of the nail, so that the screws can be quickly and accurately extended through the screw holes and used to interlock the prosthesis with the surrounding bone.
The device used in U.S. Pat. No. 4,667,664 includes a frame adapted to be secured to the proximal end of the intramedullary nail. A target mechanism is disposed at the opposite end of the frame from that end which is affixed to the proximal end of the nail. This target mechanism is arranged so that it can be moved in four degrees of movement, thereby facilitating precise coaxial alignment with each blind screw hole through the distal end of the nail. The described four degrees of movement are each independent of each other and are, of course, movement relative to the axis of the blind screw hole. After the target mechanism has been aligned, using conjunctively a standard x-ray device, a drill is employed to drill through the bone along the indicated screw axis, with the drill bit passing successively through the blind screw holes in the distal end of the nail and into the bone on the opposite side of the nail.
In the case of the device and technique disclosed in U.S. Pat. No. 4,667,664, several manual manipulations of the target through the various degrees of freedom of movement are required prior to the time that proper alignment is achieved, and the x-ray device must either be switched on and off a number of times during this manipulation, or allowed to remain on with consequent exposure of the physician or technician to x-rays during such alignment and adjustment manipulations. It is also, of course, necessary to have adequate room or space to enable the relatively lengthy device to be attached to the proximal end of the nail and extended along the limb to the location where the distal end of the nail is approximately located.
Olerud et al U.S. Pat. No. 4,625,718 discloses an apparatus useful for forming transverse bores through a fractured bone in registry with the transverse screw holes of an orthopedic locking nail. The apparatus includes an elongated holder to accommodate an aiming member which is adapted to be brought into the beam path of an x-ray apparatus by manual manipulation of the elongated holder. A reception head is adapted to receive a drill rotatably supported in the holder. A power drive device is supported by the holder for rotatably driving the reception head, and the drill supported therein. The reception head is made of a material transparent to x-ray radiation so that proper alignment of the drill is thought to occur when the drill, as represented by a dark central bulls-eye spot, is shown by the x-ray monitor to be centered in the circular image of the reception head material transparent to x-ray radiation. The portrayal of this configuration on the monitor also requires that the drill and the reception head be coaxially aligned with the screw holes through the locking nail.
In this device, hand grips are provided to facilitate the hand manipulation of the elongated holder at a time when the beam of x-rays is projected onto the reception head, and the drill bit located toward the center of the elongated holder. There is thus exposure of the physician or his assistant to x-rays at this time. Moreover, the hand-held jig is difficult to hold steady so as to be assured that the drill is proceeding evenly and directly along a line which is coaxial with the axis of one of the screw holes formed through the orthopedic locking nail.
Cho U.S. Pat. No. 4,257,411 discloses a drill guide used for drilling a tunnel or hole through a portion of the femur in a precise manner, so that the drill exit is precisely controlled, and the drill tip is located in a very critical position for the purpose of reconstructing the interior cruciate ligament of the knee. The surgical tool drill guide disclosed in this patent is characterized in having first and second upright rods carrying tubular first and second drill sheaths on their respective distal ends in relation to a transverse mounting means on which the uprights are mounted by the use of sliding heads carried at their proximal ends. This type of jig or drill guide tool permits the first and second drill sheaths to be brought up tightly against opposite surfaces of the femur so as to provide a continuing and exact axial alignment for the drilling of the bony tunnel. The way in which the upright members which carry the drill sheaths are movably adjustable has some similarity to the present invention, as do the tubular drill guides carried at the ends of these parallel upright members.
In U.S. Pat. No. 4,541,424 to Grosse et al, there is disclosed a distal aiming device which undertakes to aim drills in a direction which is coaxially aligned with a pair of screw holes in an orthopedic locking nail. The aiming device has a portion which is detachably secured to the proximal end of the locking nail. An elongated rod or bar carries a drill or pin aiming head at one end opposite the end of the nail which has a pair of screw holes extending transversely therethrough. The aiming head is capable of being moved in a direction parallel to the axis of the orthopedic locking nail. Two adjusting pins can be extended through the aiming head in a direction normal to the axis of the locking nail, and it is possible with the aid of the aiming device to perform a pre-adjustment of the aiming head relative to the locking nail. The adjusting pins are adapted, by movement of the aiming head, to be coaxially aligned with the center axes of the two transverse bores or screw holes formed through the locking nail. All of this measurement and alignment in relation to the transverse screw holes through the locking nail is accomplished before the locking nail is driven into place in the medulla of the bone. As previously stated, the device for aligning the pins is then secured to the proximal end of the nail, and it is assumed that the axes of the bores of the aiming head through which the alignment pins first extended will still coincide with the axes of the transverse screw holes through the locking nail. A requirement for such alignment remaining true, however, is that the locking nail has not been bent or deformed during implantation. This is checked by means of an x-ray apparatus which reveals if no circular opening is depicted on the monitor of the x-ray apparatus. A re-adjustment of the aiming head is then necessary and is performed by repeating all of the steps, including extraction of the nail from its position within the bone. Once the proper alignment is achieved in the manner described, the hole can be drilled through the bone to enable screwing in of transverse screws through the bone and through the transverse screw holes or openings in the locking nails.
Bosacco U.S. Pat. No. 3,670,724 discloses a hip replacement prosthesis which comprises an artificial ball mounted on, or integral with, an intermediate portion which abuts the end of the bone in question. A shank or stem having a plurality of screw holes is attached to the intermediate portion and is intended for intramedullary insertion. The intermediate portion has at least one locating hole and the stem has a plurality of axially spaced holes formed therealong. Although the stem is inserted into the medulla, and its holes are therefore obscured from view, the locating holes in the intermediate portion remain exposed. Therefore, a rectangular post can be fitted into the locating holes and used to properly position a template which is attached to the post, and which carries a plurality of screw holes. These screw holes are spaced and positioned so that when they are in place, and the template is attached to the post, the screw holes in the template are congruent with, or in registry with, the holes in the stem. This then facilitates the extension of holes by drilling transversely through the template, and through the near bone cortex, through the stem holes, and finally, into the far cortex portion of the bone. After such drilling by the use of the template, the template is removed and screws are then emplaced through the aligned holes in the bone and in the stem.
This system, as described in U.S. Pat. No. 3,670,724, again depends for accuracy upon the end of the stem, where the post is located and to which the template is attached, remaining in a precisely fixed spatial relationship to the distal end of the elongated stem. This precision, of course, is decreased by any warping or distortion in either the template or the stem.
In U.S. Pat. No. 3,782,373 to Smythe, a drill jig used in conjunction with a femoral prosthesis is disclosed. The drill jig includes a blade or insert which is shaped like the shank portion of the femoral prosthesis which is to be used, and is initially fitted into, and seated in, the femur medulla in substantially the same manner as the prosthesis will be seated in the femur. The insert or blade of the jig contains one or more guide bores for a work tool which form one or more holes in the femoral bone for the purpose of accommodating the screws subsequently screwed through the bone and through aligned holes in the shank of the actual femoral prosthesis after it is fitted in place. Thus, in this case, the holes are initially drilled through the bone and the femoral prosthesis device is then inserted into the bone until the preformed holes therethrough are brought into alignment with the holes previously drilled through the bone.
Another jig used for a femoral prosthesis device used in performing hip prosthesis surgery is disclosed in Deyerle U.S. Pat. No. 3,814,089. The jig disclosed in this patent is a generally U-shaped member which carries a short leg which can be screwed or fastened to the upper end of a hip or femoral prosthesis after it has been placed in position. The femoral prosthesis carries a plurality of axially spaced holes in the blade or shank part of the prosthesis driven into the femur. The dimensions of the jig are such that once it is bolted to the top of the prosthesis, the second and relatively long leg of the jig, which will extend down outside the leg of the patient, will have a plurality of axially spaced holes therein precisely aligned with those holes carried in the blade part of the femoral prosthesis already in place. It is therefore possible to use the holes through the jig to guide the drill in drilling through the bone in alignment with the axes of the several holes formed in the prosthesis. Since the jig structure is releasably assembled to the head or the top of the prosthesis, it can be quickly removed after the holes have been drilled, and the pins placed in position.
This type of jig can be considered fairly reliable because of the relatively short distance from the point that it attaches to the femoral prosthesis to the location of the holes in both the prosthesis and the long leg of the jig. This allows little opportunity for misalignment.
U.S. Pat. No. 4,570,624 to Wu discloses a universal guide device for inserting parallel pins, which device includes an elongated bar having a plurality of blocks slidable along the bar, and adapted to be adjustably locked in position on the bar. A transverse opening is formed through each of these blocks so that the openings through the blocks are parallel to each other. A removable sleeve is provided, and has a complementary external configuration corresponding to the internal configuration in the opening or bore through each block. Each of these sleeves has a serrated end face for engagement with the bone for holding the sleeve in position at a time when a drill stem is extended through the opening for drilling a hole for the purpose of inserting a surgical pin in the hole formed by the drill. The sleeving may be changed out according to the diameter of the drill bit to be used.
In Ulrich U.S. Pat. No. 4,292,964, a method and apparatus for pinning a fractured pelvis is disclosed. The apparatus is a jig or guiding apparatus which includes an elongated member provided with a pair of longitudinally spaced, transversely projecting arms slidable along the elongated member. These arms have outer ends which are provided with coaxially aligned cannulas having points directed at each other and separated by a space. The fractured bone is positioned in the space between the cannulas with the points engaging the fractured bone. Holes are formed in the bone surface by drilling through the cannulas.
Next a relatively small guide rod is inserted axially through the cannulas and through the fractured bone which is engaged between the cannulas. The guide apparatus is then disengaged from the bone, but the small diameter guide rod is left in place in the bone, and a tubular drill bit is fitted over one end of the guide rod and a bore is drilled through the bone along the guide rod while the bit is guided through the bone along this rod. The guide rod is then withdrawn from the bit which itself is left in the bore through the fractured bone. Finally, the bit is pushed axially out of the bore that it has formed, and is replaced by a bone pin whose ends are axially oppositely braced against the opposite ends of the fractured bone. This patent, while interesting for the drilling and pinning technique disclosed, is not concerned with alignment of drill holes with blind screw holes formed in the end of an orthopedic nail which is obscured from view until the time that the screws are actually extended through the screw holes therein.